Hitler and the Nazis took back the Saarland with a political vote on January 13th 1935. The Plebiscite was over seen by two judges from Holland and Italy and 90.3% of the citizens voted it to return back to Germany. When it was returned to Germany it helped with rearming their army.
Hitler introduced conscription to Germany and gained many more troops. Every male had to join and serve the army. With these troops, Hitler remilitarized Rhineland and violated the Treaty of Versailles.
Hitler helped Franco, the Spanish dictator, win the Civil war on Spain. This movement helped Hitler test out his new army and weapons.
Hitler demanded that Austria join with Germany. German troops entered Austria without Britain, France, or USA to challenge him. Once again, Hitler violated the Treaty of Versailles.
Hitler demanded Lebenstraum for Germans so Neville Chamberlain gave him the Sudetenland. This action was called the Munich agreement and used the policy Appeasement.
Hitler broke the Munich agreement by invading the rest of Czechoslovakia.
Germany and the Soviet union signed a pact that guaranteed the two countries won't fight. The Soviet union aided Germany in her military in exchange for land. Germany betrayed the Soviet Union almost two years later.
Germany invaded Poland and violated the Treaty of Versailles again. This action forced the UK to declare war on Germany and start world war two.